Hollow Polyester Research Articles

Estimating material properties of solid and hollow fibers in suspension using ultrasonic attenuation.

Estimates of the material properties of hollow fibers suspended in a fluid using ultrasound measurements and a simple, computationally efficient analytical model are made. The industrial application is to evaluate the properties of wood fibers in paper pulp. The necessity of using a layered cylindrical model (LCM) as opposed to a solid cylindrical model (SCM) for modeling ultrasound attenuation in a suspension of hollow fibers is evaluated. The two models are described and used to solve the inverse problem of estimating material properties from attenuation in suspensions of solid and hollow polyester fibers. The results show that the measured attenuation of hollow fibers differs from that of solid fibers. Elastic properties estimates using LCM with hollow-fiber suspension measurements are similar to those using SCM with solid-fiber suspension measurements and compare well to block polyester values for elastic moduli. However, using the SCM with the hollow-fiber suspension did not produce realistic estimations. In conclusion, the LCM gives reasonable estimations of hollow fiber properties and the SCM is not sufficiently complex to model hollow fibers. The results also indicate that the use of a distributed radius in the model is important in estimating material properties from fiber suspensions.

Evaluating the Acoustic Properties of Estabragh (Milkweed)/Hollow- Polyester Nonwovens vfor Automotive Applications

Reduction in noise pollution in general and particularly in automotive industry has become an important issue that has gained the interest of numerous researchers. The present research is aimed to introduce a new product which could serve as an alternative for other commonly used sound absorbing materials. It is expected that hollow fibers due to their structure can significantly influence noise insulation performance of materials in which these fibers are incorporated. Therefore sound absorbing material compose of blend of natural hollow fibers Milkweed or as it known Estabragh and hollow polyester fibers were used to produce needle-punched nonwoven samples. Eighteen different samples were produced by varying blend ratio, mass per unit area, punching density, and frequency of the incident sound. Noise Absorption Coefficient (NAC) of the samples was evaluated using impedance test method. The evaluation procedures were designed using Taguchi method. Results showed samples solely comprise of Estabragh fibers have attained the ability to absorb noise. It was observed that NAC decreases as the amount of Estabragh in the blend is reduced. Although the results showed an increase in punching density improves NAC of the samples, however statistical analysis dismissed the effectiveness of this parameter on sound absorption characteristics of the samples. It was found that NAC increases in direct relation to increase in mass per unit area (g/m2) of the samples. This was attributed to the increase in tortuosity of the samples and the energy losses due to frictional resistance. Finally it was observed that NAC peaks at frequency of 4000 Hz.

Compression creep behaviour of polyester needle-punched nonwoven fabrics

This present study deals with the compression creep behaviour of polyester needle-punched nonwoven fabrics. Polyester fibres of three different cross-sectional shapes (round, circular hollow and trilobal) have been selected for this study. An instrument has been designed and fabricated to measure the compression creep property of needle-punched fabrics. The effect of duration of compression load, fabric weight, fibre cross-sectional shapes and reinforcing material on percentage compression creep has been studied. It has been observed that initially, compression creep decreases rapidly and with increase in time, decrease of percentage creep becomes minimal. After about 8500 min of application of the same compression load, no change in compression creep is noticed. The percentage compression creep decreases with the increase in fabric weight irrespective to fibre cross-sectional shapes of polyester needle-punched nonwoven fabrics. Trilobal cross-sectional fabric shows maximum amount of percentage compression creep at all levels of fabric weight followed by round and hollow cross-sectional polyester samples, respectively. The percentage compression creep is higher in case of fabric samples made without reinforcing material compared to the samples with reinforcing material. Hollow cross-sectional polyester fibre can be successfully used as raw material for the preparation of needle-punched nonwoven fabrics with or without reinforcing material carpet or floor mats. However, normal round cross-sectional polyester fibre only with reinforcing material can be used for the said application. Compression creep values of these selected polyester needle-punched fabric samples are much lesser in comparison with commercial market polypropylene needle-punched carpet samples.

Using Nonwoven Hollow Fibers to Improve Cars Interior Acoustic Properties

This research aims to produce nonwoven fabrics that can be used in car interior components (head liners, doors, side panels and trunk liners) to prevent noise from reaching the passenger compartment and therefore achieving comfort in the car interior. Two kinds of fibers were used, polyester and hollow polyester fibers, both of 6 denier, to produce three different fabrics of 100% polyester fibers, 75% polyester/25% hollow polyester fibers, and 55% polyester45% hollow polyester fibers. Four fabric weights were produced: 300, 400, 500 and 600 g/m2. All samples were bonded using thermal bonding technique. More results were reached and most samples have achieved the expected results for example, samples produced with high percentage of hollow fibers have recorded the highest rates of sound absorption whereas samples produced with 100% polyester fibers have recorded the lowest rates. It was also found that there is a direct relationship between weight per m2 and sound absorption efficiency. Samples produced with 55% polyester/45% hollow polyester fibers and 600 g/m2 have achieved the best results.

The Primary Study on Polyester/ Polypropylene Sound-Absorption Nonwoven Fabric

As social civilization advances, more and more people reside in the city. Consequently, the number of automobiles and locomotives increases, causing greenhouse effect and noise pollution increasingly serious. Therefore, lowering the temperature and reducing the noise in living conditions has become an urgent task, in order to save resources usage amount and to produce a low-noise dwelling environment. In this study, the sound-absorption and heat-insulation nonwoven fabrics were firstly prepared by three-dimensional crimp hollow polyester fiber (PET) fibers and Polypropylene (PP) fibers based on nonwoven processing technology, following by sound-absorption coefficient test, thermal conductivity test, as well as maximum tensile strength and maximum tearing strength tests. The results show that, 70/30 wt% PET/ PP nonwoven fabrics have the maximum tensile strength of 2.47 MPa (CD) and 1.67 MPa (MD), in addition with the maximum tearing strength of 83.96 kN/m (CD), 111.88 kN/m (MD); the 90/10 wt% PET/ PP nonwoven presents the lowest thermal conductivity coefficient of 0.0365 W/K‧m; nonwoven with three different ratios show the similar sound-absorbing curves, which all reaches the highest absorption coefficient of 0.76 at 4000 Hz.

Effects of finishing on the mechanical and thermal properties of fabrics from wool and hollow polyester fibres

The effects of finishing steps on hollow and solid polyester/wool have been studied in order to establish the processing behaviour and performance characteristics of fabrics from these fibres. The effect of hollow fibres on fabric tensile strength, pilling, and crease recovery were studied. In addition, the water vapour permeability, air permeability, thermal properties and fabric handle were investigated. The results show that finishing has no adverse effects on fabric strength. By using hollow fibres in the fabrics, the extent of pilling was reduced. Among the different steps of finishing, scouring has the most significant effect on fabric hand due mainly to the large reduction in both bending, and shear rigidity and hysteresis. The results on crease recovery, water vapour permeability and air permeability revealed that the fabric properties are more affected by the fabric structure than the type of polyester fibre. In addition, while the hollow fibre fabrics always have lower thermal conductivity than similar fabrics with solid polyester fibres, their thermal properties are greatly affected by the dyeing process.

Seven-hole hollow polyester fibers as reinforcement in sound absorption chlorinated polyethylene composites

A series of thin, lightweight and low-cost sound absorption composites consisting of chlorinated polyethylene (CPE) and seven-hole hollow polyester fibers (SHPF) were fabricated. The sound absorption property of the fiber composites was tested in an impedance tube, the morphology was characterized by a scanning electron micrographs (SEM) and the mechanical property of fiber composites was measured by strength tester. The effect of fiber content, composite thickness, and cavity depth on the sound absorption property, and the effect of fiber content on mechanical property and micro-structure were investigated. The results demonstrated that acoustical characteristics of porous materials were exhibited by mixing with SHPF. Acoustical absorption of materials increased significantly with increasing SHPF content. Furthermore, the acoustic property of composite with 20% SHPF concentration and 3 mm thickness was noted in the low frequency range, giving a sound absorption coefficient peak, 0.695 at 2500 Hz. Composite with air back cavity had resonance characteristics of a lamella with an absorption peak only occurring at a specific frequency. Compared with pure CPE of similar thickness, mechanically CPE/SHPF composite at the 1 mm thickness and 20% SHPF exhibited 228% higher tensile stress and 96% lower breaking strain. It appears from these results that CPE/SHPF composites have potential for engineering applications especially as sound absorbers.

Study of stiffness and abrasion resistance of needle‐punched nonwoven blankets

The properties of needled fabrics depend on the nature of component fibers and the manner in which fibers are arranged in the structure. Fiber properties along with the various machine and web parameters contribute to the structure that emerges from the needling operation. In this paper, the effect of machine parameters such as depth of needle penetration and punch density on fabric stiffness and abrasion resistance of needled blankets has been studied. The effect of calendering and sandwiching hollow polyester fibers between two layers of fine polyester fibers on the abrasion resistance and fabric stiffness has also been studied. It was observed that fabric stiffness first increases and then decreases as the depth of needle penetration increases. Increase in punch density leads to a decrease in fabric stiffness only at higher levels of depth of penetration due to fiber rupture. Calendering improves the fabric abrasion resistance properties but fabric stiffness also increases. Sandwiching of hollow polyester fibers between the two layers of fine denier polyester fibers improves the abrasion resistance without increasing the fabric stiffness.

Assessment of Poplar Seed Hair Fibers as a Potential Bulk Textile Thermal Insulation Material

Poplar seed hair fibers, harvested from the seed pods of one of the most common trees grown in the United States, have properties that make them ideal fibers for thermal insulation applications. This preliminary study examines some physical, chemical, and thermal characteristics of poplar fiber in relation to wool, down, and polyester. Results show that when compared to wool and down, poplar fiber has a finer diameter, is lighter in weight, and exhibits the highest fill power, a measure of a fiber’s ability to retain bulk. Thermal insulation tests reveal that although slightly less than down, poplar fiber has similar thermal resistance value (Rct) to that of wool and hollow polyester. In addition, the poplar fiber’s exceptionally large hollow core and its ability to resist wetting after treatments of solvents and laundering strongly suggest that poplar fiber has great potential as an environmentally friendly, effective, and lightweight textile bulk insulator.

Sound absorption and viscoelastic property of acoustical automotive nonwovens and their plasma treatment

Sound absorption property, viscoelastic property and the effect of plasma treatment of four automotive nonwoven fabrics on these properties are discussed in this research paper. Needle-punched fabrics used for vehicle headliner include 2 polyester fabrics made of hollow polyester fibers or solid polyester fibers, and 2 polypropylene-composite cellulose fabrics made of jute fibers or kenaf fibers, manufactured with the same web structure of apparent fabric density and fabric thickness. Hollow polyester fiber fabric has the highest sound absorption and the highest loss factor, the second highest is jute fiber fabric. The viscoelastic property is found to be related to the sound absorption property of fabric. The plasma treatment on nonwoven fabrics changes their sound absorption and viscoelastic property as well as their fabric weight and pore size. Hollow polyester fabric shows the increased sound absorption and viscoelastic property after the treatment with the increased pore sizes, while regular polyester fabric displays insignificant changes. The cellulose fabrics are more affected by plasma treatment compared to the polyester fabrics in terms of fabric weight loss and pore size, and jute fabric is more affected than kenaf fabric due to fiber weakness. The jute fabric demonstrates the decreased sound absorption and viscoelastic property, while kenaf fabric shows the increased sound absorption with the unchanged viscoelastic property after the treatment.

The design and manufacture of profiled multi-channeled hollow polyester fibers

A Numerically Controlled Electrical Discharge Machining (EDM) System was developed for the production of spinnerets that can be used to manufacture profiled multi-channeled hollow fibers with noncircular cross-section full of 16/17 holes of circular shapes. Four spinnerets of different slit shape were made, and four hollow fibers were produced accordingly. The first trial with I-type slit failed due to the adhesion between melt polymer jets when they were extruded from the spinneret and also the melts didn’t spread well. In the second trial, fibers were obtained from a spinneret with both “C” and “I” slits. Again it failed to produce results expected, as the 4 holes in the center of a fiber appeared to be larger than the other 12 holes. The third trial that produced fibers from a spinneret with “C” slit was a success. They were fibers with 15 holes of almost the same size. This technique was then adopted for mass production. This time silver electrode was used as copper electrode couldn’t achieve the goal. In the mass production, profiled hollow fibers were obtained with 17 holes of similar dimensions, uniformly distributed in the cross-section. Porosity of the fibers reached 20.2 %. It is now clear that this technique is useful for manufacturing highly porous profiled fibers with specially designed features.

Effect of hollow polyester fibres on mechanical properties of knitted wool/polyester fabrics

The physical and mechanical characteristics of hollow polyester fibres were compared with solid polyester fibres in order to establish their processing behaviour and performance characteristics. The effects of hollow fibres on fabric properties were investigated by using microscopy and tests of tensile and bursting strength, pilling, abrasion resistance, water vapour permeability, and handle. The results show that tensile strength of hollow polyester fibres and yarns are negatively affected by the cavity inside the fibre. Hollow fibres also have higher stiffness and resistance to bending at relaxed state. Fabrics made from hollow polyester/wool blends and pure wool fabrics show three distinguishable steps in pilling. During pilling, hollow fibres break before being pulled fully out of the structure, leading to shorter protruding fibres. Microscopy studies showed that the breakdown of hollow fibres started during entanglement by splitting along the helical lines between fibrils. KES results showed that the friction between fibres and the fibre shape are the most important parameters that determine the fabric low stress mechanical properties. However, in some aspects, the hollow structure of the fibre does not have a significant effect.

Preparation and Physical Properties of Hollow Polyester Filaments with High Breathability, Water Absorption and Release Rates

This paper reports the preparation of hollow polyester filaments with high water absorption and release rates, and the study of their physical properties using differential scanning calorimetry, thermogravimetric analysis, density gradient, gel permeation chromatography, rheometry and statistical regression analysis. Four readily soluble poly(ethylene glycol)-modified cationic dyeable poly(ethylene terephthalate) (PEG-CDPET) polymers were prepared, with 3 mol % of the sodium salt of dimethyl 5-sulfo-isophthalate (SIPM). The poly(ethylene glycol) (PEG) contents were 3 and 6 wt% and the number-average molecular weights ([Formula: see text]) of the PEG were 600 and 8000 (g/mol). Blends of regular PET and PEG-CDPET were spun into hollow filaments. These hollow filaments were then drawn and treated with aqueous sodium hydroxide. The crystallinity of the PEG-CDPET polymers declined as the PEG content increased, given a fixed SIPM content. Furthermore, the crystallinity of the PEG-CDPET polymers declined as the [Formula: see text] of the PEG increased for the same SIPM and PEG contents. The SIPM and PEG segments did not change the original PET unit cell. The sodium sulphonate (–SO3Na) functional groups and the PEG molecules were only on the crystal surface and in the amorphous regions. Obviously, the rate constants for alkaline hydrolysis were in the order: PEG-CDPET polymer<<CDPET polymer<regular PET polymer. The water-absorption and release and the heat retention properties of alkali treated PET/PEG-CDPET polyblend hollow filaments were better than those of the regular PET filaments. The porous nature of the large filaments (from 0.02-1 μm in diameter) was observed after alkali treatment of the PET/PEG-CDPET polyblend hollow filaments. Additionally, the hollowness of the PET/PEG-CDPET polyblend filaments was observed to increase from 40 to 42% after alkali treatment.

10.4313/TEEM.2013.14.5.231

In this paper, the thermal diffusivity of composites comprising hollow carbon microtube (CMT) filler and unsaturated polyester resin (UPR) have been investigated. The thermal diffusivity of the CMT-UPR composites was increased to 4.056 W/m K at 50 wt% filler loading after reaching a minimum value of about 0.210 W/m K at 1 wt%. At higher filler loading, the mechanical and electrical properties of composites are typically changed. Therefore, the properties of CMT-UPR composites were determined using ASTM methods. The surface and volume-resistivity reach minimum values of 10 7 Ohm/sq and 10 8 Ohm-cm at 50 wt%, and maximum values of 10 17 Ohm/sq and 10 15 Ohm-cm for neat UPR. The distribution of CMTs in the UPR matrix was analyzed by scanning electron microscope (SEM). The thermal behavior of the CMT-UPR composites was determined by differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA).

Heat Transfer Characteristics of Nonwoven Insulating Materials

The thermal insulating abilities were evaluated using the guarded hot plate technique (ASTM D 1518-77) for the following selected nonwoven insulating materials: air-laid structures of low linear density polyolefin and low linear density polyolefin mixed with conventional linear density polyester, and carded structures of hollow polyester fiber, crimped polyester filament, and conventional polyester fiberfill. The thermal resistance of the materials varied directly with thickness, but on a per thickness basis the air-laid structures provided more thermal resistance than the carded structures. The thicker, low linear density, air-laid structure was an exception in that it did not exhibit as large an advantage over the carded structures as did the other air-laid struc tures. Under the conditions of the guarded hot plate apparatus, correlations of intrinsic thermal conductivity with the structural characteristics of the insulators indicated that the proportion of heat loss by convection was lower for the air-laid structures than for the carded structures. This reduction of heat loss by convection was due to high tor tuosity of the air flow path and larger fiber surface area. Each nonwoven insulator was subjected to 10 launderings to evaluate the effect of this action on thermal properties, thickness, air permeability, and weight. The mixed linear density, air-laid structures, hollow fiber insulator, and conventional fibafill decreased markedly in thermal resistance, while the low linear density insulators and the crimped polyester insulator exhibited only small changes as a result of the laundering process.

FIELD EVALUATION OF A PHEROMONE TO DETECT ADULT RUSTY GRAIN BEETLES, CRYPTOLESTES FERRUGINEUS (COLEOPTERA: CUCUJIDAE), IN STORED GRAIN

AbstractInsect-detection traps baited with the synthetic aggregation pheromones of the rusty grain beetle, Cryptolestes ferrugineus (Stephens), were inserted into grain stored in primary elevator annex bins and in farm bins, or suspended in partly full or empty bins and outside under the eaves of bins. The mixture of the synthetic pheromones 4,8-dimethyl-E,E-4,8-decadienolide (ferrulactone I) and (Z)-3-dodecen-11-olide (ferrulactone II) was released from hollow polyester fibers (0.203 mm ID) positioned in the interior of the insect-detection trap. In annex bins, the number of beetles found in baited traps after 1 week ranged from 0 to 7300. In these bins, more beetles were found in traps at a depth of 30–60 cm than at 150–250 cm, and in traps with 2 fibers containing pheromone rather than with 1 fiber. In farm bins, baited and unbaited traps were relatively ineffective at grain temperatures below 14 °C. More beetles were found in baited than in unbaited traps in farm bins but the numbers were small and the differences were not significant. Few beetles were found in traps suspended in partly full or empty farm bins and none in traps suspended outside under the eaves.